稠油油藏污水活性碱/聚二元复合驱室内试验研究

Laboratory test of active alkali-polymer binary combination flooding with produced sewage in heavy oil reservoir

羊三木油田碱/聚驱先导试验存在现场污水配制碱/聚二元复合驱体系时出现结垢堵塞地面管线、聚合物严重降解等问题,为此开展了污水配制新型碱/聚合物二元复合驱体系研究。采用抗钙镁结垢能力强、降低界面张力幅度大的活性碱与污水聚合物匹配,分析在污水配制条件下,不同碱型与聚合物匹配的驱油能力,以及在原油黏度高达530mPa·s时能否继续开展二元复合驱的问题。研究结果表明:原油黏度为530mPa·s,污水配制活性碱/聚合物二元复合体系溶液黏度为45mPa·s时,油水界面张力达到10-3数量级,活性碱/聚合物二元复合驱比纯水驱提高采收率17%以上;在原油黏度确定及油水界面张力已降至超低值时,超过碱/聚二元体系溶液浓度技术临界点后,即使继续增加溶液黏度,采收率也不会大幅度增加。该研究为普通稠油油藏注水开发后期化学驱提高采收率提供了新型有效的技术手段。

In the alkali-polymer pilot test of Yangsanmu oilfield, scaling often led to surface pipeline plug and polymer degradation while preparing combination flooding system with produced sewage. A new active alkali with strong capacity of calcium and magnesium scale resistance and decreasing interracial tension was adopted to prepare with produced water polymer. This paper discusses the oil-displacement capacity when different alkali matches with polymer, and whether binary system flooding can be carried out when viscosity of crude oil reaches 530 mPa.s. Research indicates that oil-water interracial tension reaches magnitude of 10^- 3, and recovery factor with binary system flooding increases about 17% compared with pure water flooding, at oil viscosity of 530 mPa＇s and alkali-polymer binary solution viscosity of 45 mPa＇s prepared with produced water. Given crude oil viscosity and ultra-low oil- water interracial tension, once the system concentration exceed technologic critical point, continuous increase of solution viscosity will not obtain the large increase of recovery factor. The research provides a powerful technical means for enhanced oil recovery with chemical flooding in the late stage of water injection development in ordinary heavy oil reservoir.